For example, a FMCW (Frequency-Modulated Continuous-Wave) radar is configured to include: an antenna section that transmits a radar wave and receives a reflected wave of the radar wave; a high-frequency circuit section that generates a high-frequency signal, mixes a reception signal outputted from the antenna section with the high-frequency signal and extracts a frequency component equal to the difference between the frequencies of the two signals; and a low-frequency circuit section that processes a low-frequency signal representing the frequency component and thereby obtains necessary information.
Moreover, as configurations of arranging the above sections on printed boards, there are known both a configuration of arranging the antenna section and the high-frequency circuit section on a front face of a single printed board and the low-frequency circuit section on a back face of the same (see Patent Document 1) and a configuration of arranging the high-frequency circuit section and the low-frequency circuit section on a front face of a single printed board and the antenna section on a back face of the same (see FIG. 5).
In addition, as illustrated in FIG. 5(a), the low-frequency circuit section is configured with: an amplifier 22 that amplifies the low-frequency signal; a filter 24 that performs, on an input signal, filtering for allowing only frequency components within a predetermined range to pass therethrough; an A/D converter 26 that converts an analog signal into digital data; a microcomputer 28 that performs signal processing based on the digital data; and a power supply circuit 29 that supplies each part of the apparatus with electric power necessary for operation.